The invention relates to a method for controlling fluid flow through a compressed fluid system, and more particularly the invention relates to a method for controlling fluid flow through a compressed fluid system by measuring the actual vacuum at the compressor inlet valve, comparing the actual vacuum to a predetermined vacuum required to produce the required fluid flow, and then opening or closing the compressor inlet valve to achieve the required predetermined inlet vacuum.
Any compressed fluid system used to supply compressed fluid to actuate a pneumatically powered machine, tool or other device must provide the compressed fluid to the pneumatically actuated object of interest at the requisite pressure. Therefore, during operation of such a system, it is necessary to continuously monitor the actual pressure of the compressed fluid that is being supplied by the compressed fluid system. Typically, in such compressed fluid systems, a pressure sensor or other suitable device is connected to the flow line and measures the actual pressure of the compressed fluid being delivered to the pneumatically actuated object of interest.
If the actual pressure of the supplied compressed fluid is less than the predetermined required supply fluid pressure, the compressor inlet valve is opened and the compressor is loaded, thereby increasing the supply pressure of the compressed fluid. The compressor remains loaded until the supply pressure reaches the predetermined required pressure. If the actual supply pressure is greater than the predetermined required compressed fluid supply pressure, the compressor inlet valve is closed and the compressor is unloaded thereby lowering the compressed fluid supply pressure. The inlet valve is closed until the compressed fluid supply pressure lowers to the predetermined required pressure value.
In conventional compressed fluid systems, compressed fluid supply pressure is measured, compared to the required supply fluid pressure and the compressor is simply loaded or unloaded to attain the requisite supply pressure. Thus conventional compressed fluid systems attempt to supply compressed fluid at a particular pressure by measuring the supply pressure and effecting the position of the inlet valve as required. Conventional compressed fluid systems do not attempt to attain a specific compressor flow.
Thus conventional compressed fluid systems, achieve the requisite supply pressure without considering the flow and this is an acceptable method for maintaining the requisite supply line pressure for most pneumatically actuated applications since, in most applications, maintaining a certain fluid pressure in a compressed fluid system produces the required compressor flow to match a demand. However, this conventional method does not ensure that the requisite flow will be supplied to pneumatically actuated processes that are dependant on the fluid flow. In a system that is flow dependent, where it is critical to the process to maintain the requisite flow, it is necessary to develop a method for matching flow to demand.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.